Which part of nephron of the human kidney is responsible for filtration of blood for excretion?
- A.Collecting duct
- B.Renal vein
- C.Ureter
- D.Bowman's capsule
Correct answer
Explanation
The correct answer is D, Bowman's capsule. Each human kidney has about one million nephrons, and every nephron begins with a cup-shaped Bowman's capsule that encloses a knot of capillaries called the glomerulus. Blood enters the glomerulus under pressure, and water, salts, glucose, urea and other small molecules are pushed out through its walls into the capsule; this is ultrafiltration, the first step of urine formation. Proteins and blood cells are too large to pass and stay in the blood. The filtrate then flows through the tubule, where useful substances such as glucose and most of the water are reabsorbed. A, the Collecting duct, only gathers urine from many nephrons and carries it to the pelvis of the kidney. B, the Renal vein, carries filtered blood away from the kidney and is not part of a nephron. C, the Ureter, is the tube that takes urine from the kidney to the bladder. Exam tip: Bowman's capsule plus glomerulus is the Malpighian body, the filter of the nephron.
Practice Questions
View allThe fact that the planets move around the Sun, not in circles but in ellipses, was first demonstrated by
- A.Galileo
- B.Martin Luther
- C.Johannes Kepler
- D.Copernicus
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In 1609 Kepler showed that the planets move around the Sun in elliptical orbits, with the Sun at one focus of the ellipse.
Read the full explanation →Which one of the following statements is correct?
- A.Urea is produced in liver.
- B.Urea is produced in blood.
- C.Urea is produced from digestion of starch.
- D.Urea is produced in lung and kidney.
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Liver cells turn the toxic ammonia released from the breakdown of amino acids into urea through the ornithine cycle, also called the urea cycle.
Read the full explanation →Which one of the following is the correct sequence of passage of light in a compound microscope?
- A.Condenser-Objective lens-Eyepiece-Body tube
- B.Objective lens-Condenser-Body tube-Eyepiece
- C.Condenser-Objective lens-Body tube-Eyepiece
- D.Eyepiece-Objective lens-Body tube-Mirror
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Light passes through the condenser to the specimen, is picked up by the objective lens, travels up the body tube and reaches the eye through the eyepiece.
Read the full explanation →Which one of the following statements regarding haemoglobin is correct?
- A.Haemoglobin present in RBC can carry only oxygen but not carbon dioxide.
- B.Haemoglobin of RBC can carry both oxygen and carbon dioxide.
- C.Haemoglobin of RBC can carry only carbon dioxide.
- D.Haemoglobin is only used for blood clotting and not for carrying gases.
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It binds oxygen at its iron-containing haem groups and carries some carbon dioxide on its protein chains. Each haemoglobin molecule has four polypeptide chains and four haem groups, and each haem iron can hold one oxygen molecule, forming oxyhaemoglobin in the lungs.
Read the full explanation →Which one of the following statements regarding histone proteins is correct?
- A.Histones are proteins that are present in mitochondrial membrane.
- B.Histones are proteins that are present in nucleus in association with DNA.
- C.Histones are proteins associated with lipids in the cytosol.
- D.Histones are proteins associated with carbohydrates in the cytosol.
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They are the proteins around which DNA winds to form chromatin in the nucleus of eukaryotic cells. Histones are small basic proteins, rich in the positively charged amino acids lysine and arginine, which attract the negatively charged phosphate groups of DNA.
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